The relationship between regional human development and geographic environment is the basis for dynamic social change, and studying the evolution of human-land relations in typical regions can provide background knowledge for global change studies. This study is based on GIS and spatio-temporal statistical techniques, combined with the analysis of toponymic cultural landscapes, to study ethnic minority regions of southeastern China. The results show that: (1) The geographical environment of the region will affect the naming of villages, and the orientation and family name are the most common; the frequency of plants, pit (keng), animals, and flat (ping) is also very high. (2) Han settlements and She settlements have obvious spatial differentiation, and in general the Han distribution area is lower than that of the She. Han settlements are mainly distributed in plain areas along rivers with elevations less than 200 m; She settlements are mainly distributed in hilly areas (200~500 m) and low mountain areas (500~800 m). (3) The results of quadrat analysis and nearest neighbor index analysis show that both Han and She settlements are clustered in the spatial distribution pattern, and the distribution of She settlements is more clustered than that of Han, with more dense settlements at a certain spatial scale. The regional cultural landscape is the result of the development and evolution of human-land relationship, and the comprehensive analysis of cultural landscape can understand the process of human-land relationship in a small region. The settlements in the region are indicative of the geographic environment in terms of village naming, spatial pattern, elevation differentiation and relationship with rivers, which can reflect the environmental adaptation process of human activities.
Background At present, the research on achiral drug and pesticide residue detection methods is still the mainstay at home and abroad, and there is still a lack of systematic research on the enantiomeric analysis of chiral drugs and pesticides. Objective In order to prepare a novel chiral stationary phase, whose “multi-mode” chiral separation chromatographic performance and its utility was verified. Methods An S-(-)-2-benzylamino-1-phenylethanol mono-derivative β-cyclodextrin bonded stationary phase (BzCSP) was prepared based on the “thiol-ene” addition reaction. The chiral compounds including four types of chiral compounds were used as “probes”, and their chiral chromatographic properties were evaluated. Furthermore, a new LC-MS/MS method for the determination of the enantiomeric residues of three chiral pesticides in five kinds of fruits and vegetables was established. Results The study found that the novel stationary phase was suitable for a variety of chromatographic modes (normal phase mode, reversed-phase mode, polar organic mode). The resolutions of hexaconazole (Hex), tebuconazole (Teb) and triticonazole (Trit) enantiomers could be up to 2.31, 1.68, and 1.48, respectively, within 30 min under reversed-phase chromatography. Based on the optimal chromatographic and mass spectrum conditions, a new LC-MS/MS quantitative method for the Hex, Teb and Trit enantiomers was established by multi-reaction positive ion monitoring (MRM). The detection limits (LODs) of enantiomers were less than 0.89 µg kg−1 for Hex, 0.93 µg kg−1 for Teb and 0.93 µg/kg for Trit, the averaged recoveries of enantiomers were in the range of 75.8–106.3% for Hex, 77.4–116.3% for Teb, and 78.7–113.4% for Trit. The method had good reproducibilities with the RSDs (<5%) for intra-day and (<7%) for inter-day. Conclusion The established method had the characteristics of good selectivity, high sensitivity, strong resistance to matrix interference, and good reproducibility. It is indicated that the stationary phase prepared by the “thiol-ene” addition reaction is a new type of multi-mode stationary phase, which has a good development value. Highlights The study reported a new method for the rapid preparation of a rare “multi-mode” chiral stationary phase BzCSP based on the “thiol-ene” addition reaction and verified the practicability of BzCSP including good selectivity, high sensitivity, strong resistance to matrix interference, and good reproducibility.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.